attiny2313_pwm.cpp

void init_pwm() {                                                                                                                                 
                                                                                                                                                  
    // outputs                                                                                                                                    
    DDRB |= (1 << 2); // PB2                                                                                                                      
    DDRD |= (1 << 5); // PD5                                                                                                                      
                                                                                                                                                  
    // Waveform Generation Mode to Fast PWM (WGM0[0:2]=7)                                                                                         
    TCCR0A = (3 << COM0A1)  // Set OC0A on Compare Match, clear OC0A at TOP                                                                       
           | (3 << COM0B1)  // Set OC0B on Compare Match, clear OC0B at TOP                                                                       
           | (1 << WGM00)                                                                                                                         
           | (1 << WGM01);                                                                                                                        
}                                                                                                                                                 
                                                                                                                                                  
#define PWM_CLK_OFF      0                                                                                                                        
#define PWM_CLK_DIV_1    1                                                                                                                        
#define PWM_CLK_DIV_8    2                                                                                                                        
#define PWM_CLK_DIV_64   3                                                                                                                        
#define PWM_CLK_DIV_256  4                                                                                                                        
#define PWM_CLK_DIV_1024 5                                                                                                                        
                                                                                                                                                  
void set_pwm_clk(uint8_t clk_selector) {                                                                                                          
    TCCR0B = (clk_selector << CS00);                                                                                                              
}                                                                                                                                                 
                                                                                                                                                  
inline void set_pwm_PB2(uint8_t duty) {                                                                                                           
    OCR0A = duty;                                                                                                                                 
}                                                                                                                                                 
                                                                                                                                                  
inline void set_pwm_PD5(uint8_t duty) {                                                                                                           
    OCR0B = duty;                                                                                                                                 
}